1. Field of the Invention
This invention is concerned with the breaking or resolution of oil-in-water (O/W) bituminous emulsions by treatment with water soluble polymers.
2. Description of the Related Art
A great volume of hydrocarbons exist in known deposits of tar sands. These deposits occur at various places, the Athabasca tar sands in Canada being an example. The petroleum in a tar sand deposit is an asphaltic bitumen of a highly viscous nature ranging from a liquid to a semisolid. These bituminous hydrocarbons are usually characterized by being very viscous or even non-flowable under reservoir conditions by the application of driving fluid pressure.
Where surface mining is not feasible, the bitumen must be recovered by rendering the tar material mobile in-situ and producing it through a well penetrating the tar sand deposit. These in-situ methods of recovery include thermal, both steam and in-situ combustion and solvent techniques. Where steam or hot water methods are used, a problem results which aggravates the recovery of the bitumen. The difficulty encountered is emulsions produced by the in-situ operations. These emulsions are highly stable O/W emulsions which are made even more stable by the usual presence of clays. Most liquid petroleum emulsions are water-in-oil (W/O) types. These normal W/O emulsions are broken by methods known in the art. However, the bitumen emulsions which are O/W types present a much different problem, and the same demulsifiers used in W/O emulsions will not resolve the O/W bitumen emulsions.
C. W. W. Gewers, J. Canad. Petrol. Tech., 7 (2), 85-90 (1968) describes the uniqueness of emulsions encountered in the production of bitumen from tar sands.
Application Ser. No. 326,458 filed of even date claims adducts of polyoxyalkylene diamines with diisocyanates as tar sand demulsifiers.
Application Ser. No. 326,454 filed of even date claims adducts of polyoxyalkylene diamines with epichlorohydrin as tar sand demulsifiers.
Application Ser. No. 326,459 filed of even date claims ionene polymers (polyquaternary ammonium salts) as tar sand demulsifiers.